1. Field of the Invention
The subject invention relates to the problem of providing simultaneous access for a number of users to a mass storage medium.
One of the advantages of present day cable television is the provision of pay-per-view features. However, a drawback is that the viewer is locked into viewing the program at the time that the feature is provided by the cable supplier.
A new service being proposed is video-on-demand where, for example, a movie selected by the user is provided to that user when desired by the user. One problem in implementing this type system is being able to store a large number of individual movies effectively. Another problem is being able to access and deliver these stored individual movies to different users.
2. Description of the Related Art
The first problem may be addressed by the various data compression schemes in which the video information is digitized and then compressed (JPEG, MPEG, etc.). This compressed data may then be stored in a mass storage medium.
The second problem is more problematical. There are various proposals for constructing a bus system ("big bus") for connecting the mass storage medium to a distribution system, e.g. a cable system. However, the design of this "big bus" is very complicated and is not subject to expansion. In particular, to achieve a high data bandwidth, the "big bus" would have to incorporate costly ultra-high speed components, since a bus has only one data path. In addition, in a high-bandwidth parallel digital bus type system having many data lines, devices attached to the bus must be physically close to the bus, and the bus can have only a limited physical length. Furthermore, such a bus would be very expensive.